The needs of space missions are changing and with it the materials are also changing. While in the past the designers focused on a limited number of materials that have been well characterized over the years, the entry of new players into the market has meant that new needs have arisen and we are starting to evaluate the possibility of using new, more high-performance materials. Material compatibility is a primary concern given the limited availability of data. Furthermore, the ever-increasing duration of future space missions requires evaluating the long-term compatibility of all materials and fluids used to ensure sufficient durability of vehicles and equipment. In this study, the material compatibility of typical fluids used in aerospace applications is analyzed with consistent testing conditions and a complete uncertainty analysis of the results. One state-of-the-art set of fluids has been chosen as case study. The polymers to be investigated may ranging from elastomeric ones as to techno polymers The material compatibility will be evaluated by changes in volume, weight, and other relevant material properties which will be chosen based on the characteristics relevant to the specific applications. For example, by the micro hardness measurements or by mechanical testing and by FTIR to get chemical interaction's effect. This study points out the importance of material compatibility testing, especially by investigating the difference between short-term and long term compatibility through accelerated aging.